Our studies focus on aproteincomplexfrom plants knownas photosystem II (PSII), which contains the photochemical machinery associated with photosynthetic water splitting. We distinguish between the numerous electron and energy transfer events occurring in PSII by dissecting the PSII complex into smaller complexes of known polypeptide composition. We apply, then, resonance Raman spectroscopy as a structural probe and time-resolved fluorescence as a functional probe of spinach PSII. We have described our results on the kinetic characterization of a chlorophyll binding polypeptide of PSII that acts as a harvester of excitation energy. The study of this so-called antenna protein is an important first step in our effort to understand energy and electron transfer in PSII.